1. Field of the Invention
The present invention relates to an insertion apparatus including a drive section that electrically pulls a pulling member inside an endoscope operation portion including a bending operation apparatus, the pulling member making a bending portion provided in an insertion portion bend.
2. Description of the Related Art
In recent years, in a medical field or an industrial field, endoscopes including an elongated insertion portion have been used. With the endoscopes in the medical field, i.e., the insertion portion is inserted into a body from, e.g., the oral cavity or the anus to perform, e.g., observation. On the other hand, with the endoscopes in the industrial field, the insertion portion is inserted into, e.g., a piping or an engine to perform, e.g., observation.
In the endoscopes, in general, an observation optical system is provided in a distal end portion of the insertion portion. Also, on the distal end side of the insertion portion, a bending portion that bends, for example, upward, downward, leftward and rightward is provided. Furthermore, at a proximal end of the insertion portion, an operation portion including a bending operation apparatus is provided.
Then, for example, bending knobs, which provide the bending operation apparatus, and, for example, distal end bending pieces included in the bending portion are joined via wires, which are pulling members. An endoscope configured as described above enables an operator to operate the bending knobs via the fingers of his hand grasping the operation portion to pull or slacken the wires to bend the bending portion.
In recent years, motorized bending endoscopes that include drive means provided inside an operation portion of the endoscopes and enable a bending portion to be bent by operating one manipulator via fingers, the manipulator being a bending operation apparatus provided in a standing manner on the operation portion have been proposed. For example, Japanese Patent No. 3549434 indicates a motorized bending-type endoscope that is excellent in operability and independently detects a bending angle of a bending tube portion of an insertion portion and an external force applied to the bending tube portion, enabling correct recognition of the state of the bending tube portion.
The motorized bending-type endoscope includes a tensile force sensor that detects a tensile force of an angle wire, which is a pulling member, and a displacement sensor that detects a displacement of the angle wire. Also, the motorized bending-type endoscope includes means for calculating a difference value between the detected tensile force of the angle wire and a tensile force set in advance for the detected displacement of the angle wire in a state where a distal end portion of the insertion portion is not subjected to an external force. The motorized bending-type endoscope is configured so that if the distal end portion of the insertion portion is subjected to an external force when a bending portion is bent, the bending operation apparatus is actuated according to an amount of force corresponding to the difference value to make an operator aware of the reception of the external force.